This invention is related to electrical rocker switches. In particular, it is an improved rocker switch that is sealed against contamination by elements in the environment to provide a better and more reliable switch.
A rocker switch is a device having a plurality of terminals and means operated by a rocker for making and breaking electrical connections between pairs of those terminals. A rocker switch typically has two or more stable states, but the term is also applied to switches designed for manual operation by means of a rocker and having at least one stable state, with other states involving momentary operation. The possible operating combinations for a single pole-double throw (SPDT) rocker switch are maintain-maintain, maintain-momentary, momentary-maintain-momentary, maintain-maintain-maintain, and maintain-maintain-momentary. In these combinations the term maintain means a state in which a switch remains where it is placed and the term momentary means a state in which the switch remains only as long as it is held there. It is often desirable in making a switch to be able to achieve any or all of these combinations with minimum changes in manufacture.
A rocker switch includes a button that is mounted to a case to pivot about an axis or the like. A spring is typically placed in contact with the button to exert a biasing force that will maintain the button in one or more of the stable positions, and will also maintain or assist in maintaining a force on electrical contacts that are being switched into contact. When the spring is used to exert a force on a plunger that operates an actuator, the spring also supplies the force that causes the switch to toggle from one stable position to another, to move from a momentary position when an operator lets go, and to apply force to maintain electrical contact.
The principles of operation of a rocker switch such as the one of the present invention are illustrated in U.S. Pat. No. 5,158,172, entitled "Toggle Switch," which is assigned to the assignee of the present invention and which is incorporated here by reference as if set forth fully. Such a switch, like the one of the present invention, is made with either a single pole or a double pole. Either of these types may be built as a single-throw or double-throw switch. Whatever the type, single pole-single throw (SPST), single pole-double throw (SPDT), double pole-single throw (DPST), or double pole-double throw (DPDT), an actuator moves a blade to make and break electrical contacts. The shape of the actuator determines whether the switch maintains a position in which it is placed or whether it changes from that position.
The typical rocker switch is a commodity, made in relatively large numbers for industries such as boats, construction vehicles, and the like. This makes it important in designing a rocker switch to have a minimum number of parts and maximum ease of assembly as well as a permanent seal at the button and behind the panel.
Rocker switches are often specified to mount in relatively standard rectangular panel cutouts that range in length from 1.072" to 1,125" and in width from 0.490" to 0.550". To cover all standard cutouts, a rocker switch must fit into the smallest standard panel cutout and cover the largest. There are many available rocker switches that fit this description, but few or none of them are also sealed against water and dust.
It is often useful to have a light bulb in a rocker switch to indicate that the switch is on or to provide a visual indication of other information. Such a bulb is attached to the housing or other part of the switch and is allowed to shine through a transparent or translucent portion of the button that may be colored. In a two-terminal switch, the bulb must be powered from the switched terminals. In a three-terminal switch, the bulb may be powered from the switched terminals or it may be powered from an independent terminal. With four terminals, an SPDT switch can have independent control of power to the bulb, and with five or six terminals, a DPDT switch can have independent control of power to the bulb. Thus, it may be desirable to have as many as six terminals on a rocker switch. If these are blade terminals, they may be difficult to fit into a normal terminal configuration.
A number of rocker switches that are available are sealed by O-rings and the like at the rocker and are sealed at the area of insertion into the panel. All or almost all of these, however, are not sealed behind the panel. A switch that is sealed completely is protected against dust and water and may even be qualified as an explosion-proof or submersible switch.